The present invention relates to a hinge device and, more particularly, to a hinge device for a folding door.
A type of conventional folding door used, such as in an airplane lavatory, includes two door panels connected by a hinge. A hinge for a folding door of a lavatory used in Boeing commercial airliners includes two hinge members and a connection member. Each hinge member is coupled with an inner end of one of the door panels and includes a gear portion. Two ends of the connection member are pivotally coupled with the gear portions of the hinge members, respectively. The gear portions of the hinge members mesh with each other, allowing the door panels to be folded or unfolded for opening or closing purposes.
However, the conventional folding door has the following disadvantages in use:
(1) When the folding door is mounted at a site (e.g. a bathroom) and is in a closed state, the two hinge members face the inside of the bathroom, and the connection member faces the outside of the bathroom. Thus, the gear portions of the hinge members rust easily, because the gear portions are liable to be splashed by water inside the bathroom when the folding door is unfolded, reducing the smoothness of the pivotal movement of the door panels.
(2) After the folding door is mounted at the site (e.g. a bathroom), screws for fixing the hinge members to the door panels are exposed and, thus, adversely affect the aesthetical appearance and rust easily.
(3) When the folding door is in the closed state, the connection member is exposed outside the folding door and is, thus, vulnerable to destruction.
(4) A large gap exists between the door panels when the folding door is in the closed state, and the hinge members engage with each other by the gear portions only, failing to reliably secure the door panels together.
(5) Each hinge member has a column that deforms easily under impact from an external force applied improperly. This damages the meshing between the gear portions and adversely affects the smoothness of folding and unfolding operations of the door panels.
Thus, a need exists for a novel hinge device for effectively securing door panels of a folding door together in the closed state and enhancing the smoothness of folding and unfolding operations of the door panels.